The narrative of Chicago's architectural history is often interpreted as a grand march of progress from one style to the next, each reaching a new height. Part ten of our Chicago Architecture Crash Course will look at the decades when this narrative seemed to stop dead in its tracks, during the "urban crisis" of the '50s, '60s, and '70s. We'll look into why so many parts of the city were razed, how national and local politics influenced the rebuilding, and how one man's tragic death galvanized Chicago's historic preservation movement.